Misselection indicator



J 30, 1945- L.'F. REINHOLD ET AL 2,404,813

MISSELECTION INDICATOR Filed Oct. 7, 1944 2 Sheets-Sheet l July 30,1946. L F. REl N HOLD ETAL 2,404,8

MISSELECTION INDiCATOR Filed 091;. 7, 1944 2 Sheet s-Sheet 2 INVENTOIQ." LEON/MPO E FEW/mm #44752 I S sAlcb-e UNITED STATES PATENT OFFICE MISSELECTION INDICATOR Leonhard F. Reinhold,

Staten Island, N. Y., and

James A. Spencer, Teaneck, N. J., assignors to Radio Corporation of America, a corporation of Delaware Application October 7, 1944, Serial No, 557,620

9 Claims.

This invention relates to printing telegraph apparatus and more particularly to improvements in mechanisms for causing the printing of an error symbol whenever the selecting mechanism of the printer is improperly operated.

In the transmission of telegraphic code signals, quite frequently electrical disturbances cause the signals to be mutilated. The selecting mechanism then fails to operate in accordance with a true code signal and the proper character cannot be printed. In order to distinguish between a failure to print and an instance where a space should be shown between two printed characters, it is desirable to indicate the receipt of a false signal or a combination of code impulses which does not represent a true character signal.

It is an object of our invention to provide means for indicating that a false signal has been received and that the code selecting mechanism of a printer has been incorrectly operated.

It is another object of our invention to provide an error detector for use with a printer having a rotatable typewhee1 shaft and having internally notched code rings for selectively positioning the typewhee1 to print a character.

It is still another object of our invention to provide an error detector which is readily adapted for use with typewhee1 printers regardless of whether the construction of the printer is arranged to have a homing position or no homing position for the typewhee1 shaft.

Another object of our invention is to provide an error detector adaptable to a selecting mechanism for orienting a rotatable shaft, the error detector being arranged to cooperate with a search arm on the orientable shaft and to arrest the search arm in a suitable position for indicating a misselection.

Another object of our invention is to provide an error detector for use with apparatus of the type above referred to, wherein the orientable shaft is brought to an error detecting position whenever the number of selecting code rings actuated is more or less than the proper number for true selection.

Another object of our invention is to provide an error detector comprising a system of Wedge members having spacers movable along tapered portions thereof for expanding or contracting the spaces between the wedge members and so actuating a detent which is associated with a rotatable search arm for the purpose of arresting this arm in position to indicate misselection.

In a preferred type of printing telegraph apparatus for which our misselection indicator is particularly well adapted, the selecting mechanism includes internally notched code rings.

These rings are coaxially disposed with respect to a typewhee1 shaft which carries a seeker.

Selected rings are rotated through a slight angle in order to bring their code notches into alignment in different positions about their inner edges. The seeker rotates when released after setting up a certain combination of the code rings. When the seeker finds an alignment. of

code notches, it is arrested 50 that the typewheel mounted on the same shaft with the seeker may be in a position for printing a selected character. After a printing operation the shaft carrying the typewhee1 and the seeker is then permitted to resume rotation. In certain types of printers using the internally notched code rings the typewhee1 rotates from one selecting position to another and has no homing position. In another type of such printers, as illustrated in our copending application Serial No. 485,186, filed April 30, 1943, now U. S. Patent No. 2,375,828, issued May 15, 1945, a homing 5 position is provided for the typewhee1 shaft. In this. case the error detecting position is located at a slight angle to the homing position. The instant application disclose illustratively two embodiments of misselection mechanism. One embodiment is suitable for use with code ring selectors which are associated with a typewhee1 shaft having a homing position. The other embodiment is useful when no homing position is provided.

Our invention will now be described in more detail, reference being made to the accompanying drawings, in which:

Fig. 1 is a front elevation of a preferred embodiment of our misselection indicator in combination with selecting mechanism of the type having internally notched code rings; 7

Fig. 2 is a plan View of the misselection mechanism as used with a selector the orientable shaft of which has a homing position;

Fig. 3 shows a vertical cross-section of the misselection mechanism taken along the line 3--3 in Fig. 1;

Fig. 4 shows another plan view similar to that of Fig. 2, but modified for association with a selector the orientable shaft of which has no homing position; and

Fig. 5 is a perspective view showing how the rotatable stop arm I0 is arrested and released by the detent l3a.

55 The aforesaid objects of our invention are pref more or less than three.

theerror detecting lug II into the path-of the stop arm I The movementof a plurality of the spacer members 21 into position to close up the wedge members 28 has no further effect, regardless of how many code rings are actuated.

Referring now to Fig. l in connection with Fig. 1, we show a modification of the misselection mechanism which is adapted to selectors having no homing position for the typewheel shaft 9 and its associated members mounted thereon. The detent I3a has a single lug member I la which is slotted at 36, Fig. 4 is shown with three of the spacer members, 28' moved into position to allow contraction of the wedge members and movement of the detent I3a into a position corresponding to a proper selection of three code rings. In this position, the stop arm I0 is unopposed by the lug I I a and is free to pass through the notch 36. The typewheel shaft 9 is, therefore, caused to rotate to a selected position determined by the alignment of code notches in the rings I. After printing a selected character the code rings may be reset to a different combination, and, if in so doing, response is made to a mutilated signal having more or less than three marking elements, then the number of spacer members 21 which will be positioned against the narrow necks of the wedge members 23 will be In this case, the lug IIa will be caused to intercept the stop arm I0, regardless of whether the number of actuated code rings is less than three or more than three. If the number is other than 3, then the detent lever I3a will not allow the stop arm ID to pass through the notch 36. The detent lever I3a may, however, occupy any one of four positions. The first two positions in the order of its approach to the cover 3| will cause the leading side of the lug Ila to be interposed in the path of the stop arm Ill. The third position is one in which the stop arm is free to rotate through the notch 36; and the fourth position (where the detent Ill abuts the cover plate 3|) is such that the outer end of the lug Ila is caused to intercept the stop arm I 0. Whenever the stop arm I0 is arrested by the lug I la, misselection is indicated.

In the foregoing description, Figs. 3 and have not been specifically referred to, but the parts shown in the other figures and in these figures have been given corresponding reference numbers for more clearly indicating the constructional details of the misselection mechanism.

It will be apparent to those skilled in the art that various modifications of our invention may be made without departing from the spirit and scope of the invention itself.

We claim:

1. In an error detector which responds to the reception of mutilated code signals, a plurality of wedge members each separately pivoted at one end and being tapered inwardly from their free ends, a plurality of spacer rods/each having a portion slideable against the tapered edges of said wedge members, means responsive to the reception of different code elements of a-signal for independently actuating said spacer rods whereby the disposition of the wedge members is variably expanded and contracted, and means operable under joint control of said wedge members for producing an error-detecting response whenever the number of actuated spacer rods is more or less than is required for unmutilated code signal reception.

2. A device according to claim 1 in combination with a rotatable stop-arm mounted on a shaft to be variably oriented in accordance with the re- 6 ception of difierent code signals, said means for producing an error detecting response including a detent forintercepting said stop-arm. 3. In. an error detector which responds to th reception of mutilatedcode signals, a plurality of wedge members each separately pivoted at one end and being tapered inwardly from their free ends, a plurality of spacer rods each having a portion slideable against the tapered edges of said wedge members, mean responsive to the reception of different code elements'of a signal for independently actuating said spacer rods whereby the disposition of the wedge members is'variably expanded and contracted, a rotatable stoparm mounted on a shaft to be variably oriented for translating received code signals, and a detent having two lugs arranged and adapted to intercept said stop-arm at either of two positions,

namely, a homing position and an error designating position, said detent being actuated by expansion and contraction of said wedge member disposition.

4. A device according to claim 3 in which the means for actuating said spacer rods comprises a plurality of internally notched code rings and said stop-arm carries means for engagement with any alignment of notches in said code rings which may result from selective setting thereof.

5. In a device for detecting erroneous reception of code signals, a set of internally notched code rings disposed in parallel planes, each ring being settable in response to the reception of a different element of a code signal, a set of wedge members individually pivotally mounted in such position that their free ends are movable transversely with respect to said parallel planes, each of said wedge members being tapered inwardly from its free end, a set of spacers each settable under control of a different one of said code rings and each having a fingermovable along said tapered profile to determine the spacing therebetween, a typewheel shaft carrying an index arm having means thereon for searching out a point of its arrest such as is determined by an alignment of notches in said rings, and a detent constituting means for arresting said index arm in an error designating position, said detent being-operable under joint control of said wedge members whenever the number of set code rings is more or less than required for producing a code notch alignment.

6. In a device of the class described the combination of an internally notched code ring se-' lector for causing a rotatable shaft to be arrested in dilferent selected positions, means including a stop-arm mounted on said shaft for causing its arrest, a plurality of independently pivoted wedge member having inwardly tapered free ends, a plurality of spacer rods each having pivotal connection with a different one of the code rings in said selector and each adapted to engage slideably along the tapered edges of said wedge members thereby to vary the expanse of the same, and a detent adapted and arranged to intercept the shaft arresting means, said detent being pivoted at one end and being movable in response to the variable expansion of the wedge member disposition.

'7. The combination according to claim 6 in which said detent is provided with two lugs, one for intercepting the shaft arresting means at a homing position, the other for intercepting the same in an error designating position.

8. The combination according to claim 6 in which said detent is provided with a slotted lug 7 movable transversely withrespect to the lane of rotation of said shaft arresting-'meansg the control of such movement being-'suehthat' aportion of the lug-oneitherside of 'said' slot will stop the shaft in an error designating position;

9. Ina device of the classdescribed, a rotatable shaft, a plurality of selector rings for determin ing a position of orientation at which said shaft is. to.v be stopped, means including an exploring arm mounted. onsaid shaft: and cooperating with. said selector. rings. for arresting the. rotation of said shaft, aiwedge-member assembly having. a. plurality of spatulate bars pivoted: at; one end 8 thereof, a plurality of spacer rods each individu ally slideable along the inclined edge of said bars thereby to vary their expanse, eachof said spacer rods being separately controlled. by a respective one of said selector rings, a pivoted: detent setta-ble in accordance with the degree'of expansion of said spatulate bars caused by the actuated spacer rods, and an extension on said I exploring arm engageablewith said detent Whenever anerror in-code signal reception is tobe designated} LEONI-IARD IE. REINHQLD.

JAMES A. SPENCER; a 

